Indirect extrusion with skull skimming

ABSTRACT

A METHOD OF INDIRECTLY EXTRUDING A METAL BILLET DISPOSED IN A CONTANER MOUNTED BETWEEN A DIE MEANS AND A CONTAINER BLOCKING MEANS BY APPLYING COMPRESSIVE FORCES TO OPPOSITE ENDS OF THE BILLET THROUGH THE BLOCKING AND DIE MEANS SO THAT RELATIVE MOVEMENT OF AT LEAST ONE OF THE DIE AND BLOCKING MEANS TOWARD THE OTHER WILL EXTRUDE THE BILLET THROUGH THE DIE MEANS WITH THE BLOCKING MEANS AND DIE MEANS ENDING UP NEARING ONE END OF THE CONTAINER. THEREAFTER REMOVING THE UNEXTRUDED BILLET RESIDUE FROM THE CONTAINER BY MOVING BOTH THE BLOCKING MEANS AND THE DIE MEANS TO THE OTHER END OF THE CONTAINER.

Feb. 16, 1971 G. E. MONIE ET AL 3,563,079

INDIRECT EXTRUSION WITH SKULL SKIMMING Filed Nov. 21, 1968 2 Sheets-Sheet 1 v 42 2O 32 5| 1 56 I FIG I 2 7 29 4| 46 [/35 72 k I Q FIG-3 INVENTORS GEORGE E. MONIE WARREN e. WHITING THEIR ATTORNEYS Feb. 16,- 1971 M NIE ET AL 3,563,019

INDIRECT EXTRUSION WITH SKULL SKIMMING Filed Nov. 21, 1968 2 Sheets-Sheet 2 20 45 FIG-4 28 I INVENTORS- GEORGE E. MONIE WARREN e. WHITING L. T J THEIR ATTORNEYS United States Patent O INDIRECT EXTRUSION WITH SKULL SKIMMING George E. Monie, Henrico, and Warren G. Whiting,

Richmond, Va., assignors to Reynolds Metals Company, Richmond, Va., a corporation of Delaware Filed Nov. 21, 1968, Ser. No. 777,621

Int. Cl. B21 c 23/00 U.S. Cl. 72255 7 Claims ABSTRACT OF THE DISCLOSURE A method of indirectly extruding a metal billet disposed in a container mounted between a die means and a container blocking means by applying compressive forces to opposite ends of the billet through the blocking and die means so that relative movement of at least one of the die and blocking means toward the other will extrude the billet through the die means wtih the blocking means and die means ending up nearing one end of the container. Thereafter removing the unextruded billet residue from the container by moving both the blocking means and the die means to the other end of the container.

BACKGROUND OF THE INVENTION A major problem during the indirect extrusion of metal billets is the accumulation of skull on the walls of an associated billet container. Such skull must be periodically removed in order to assure an eificient indirect extrusion operation. The word skull is generally used in the metal extrusion industry to describe accumulations of unwanted materials on the walls of a billet container and may include a layer of unextruded metal, metal oxide, and lubricant deposited between the extrusion die and the container wall during extrusion.

SUM MARY This invention provide an efficient and economical method of indirectly extruding metal billets including the removal of skull from an associated billet container.

Other details, uses, and advantages of this invention will become apparent as the following description of the exemplary embodiments thereof presented in the accompanying drawings proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show an exemplary embodiment of this invention, in which FIG. 1 is a view with parts in section and parts broken away illustrating a metal billet within an associated container of an extrusion apparatus or press at the beginning of an indirect extrusion operation with a skim block being held in position against the unextruded billet at one end of the container and with an associated extrusion die being held in position against the billet at the oppoite end of the container;

FIG. 2 is a view similar to FIG. 1 after the billet has been extruded and with the billet butt and extrusion die arranged adjacent the skim block at the one end of the container;

FIG. 3 is a view showing the butt, extrusion die, and skim block after they have been moved from the one end of the container to its opposite end to skim skull accumulations from the inside wall of the container;

FIG. 4 illustrates the press with the skim block moved within the container and the accumulated skull, billet butt and die being sheared away from an elongated metal member formed by extruding the billet;

FIG. 5 illustrates a billet loader holding a new billet to be extruded and an associated extrusion die between the front platen of the extrusion press and the container 3,563,079 Patented Feb. 16, 1971 DESCRIPTION OF ILLUSTRATED EMBODIMENTS Reference is now made to FIG. 1 of the drawings which illustrates an exemplary apparatus or press 20 of the type which may be utilized to carry out the method of this invention. The press 20 has a structural portion 21 provided with a cylindrical internal surface 22 which defines a passage 23 extending therethrough and in this example of the invention the passage 23 is arranged horizontally.

A tool carrier 24 is provided and supported by the cylindrical surface 22 for axial sliding movement back and forth therealong. The tool carrier has a hollow stem portion 25 supported in a substantially cantilevered manner at the forward end thereof and the terminal end of the stem 25 is adapted to engage and firmly hold an associated die means or die 26 in an extruding position against an associated billet which is to be extruded by the press 20 and supported within an associated container 30 comprising the press 20 and in a manner as will be described in more detail subsequently. The die may be either secured or unsecured to the stem. In the description of this exemplary embodiment, it will be asumed that it is unsecured.

The press 20 has locking means in the form of a gate lock 27 which is provided for locking the tool carrier 24 and hence the hollow stem 25 and die 26 in position within the press 20. The gate lock 27 is moved from an upper unlocked position as shown at 28 in FIGS. 3-5 to a lower locked position, indicated at 29 in FIG. 1, during an extrusion operation and during such extrusion operation the stem 25 is arranged so that it extends outwardly of the front platen 32 of the press 20.

The container 30, which has an outer housing 36, may be suitably supported on the press 20 in any known manner so that it may be readily moved toward and away from the platen 32 and for reasons which will be apparent later in this specification. The container 30 has an inner cylindrical surface 33 which defines an opening or bore 34 which is adapted to receive a metal billet 35 which is to be indirectly extruded by the press 20.

The press 20 has a main ram 40 which also has a piercer 41 provided as an integral part thereof. The term piercer is somewhat inaccurate in this context, but is derived from the function of this element when the extrusion press is modified for direct extrusion of tubing. The main ram 40 and piercer 41 may be simultaneously moved from a position indicated at 42 (see FIG. 1) which is remote from the front platen 32 to a forward position closely adjacent the front platen 32 and as illustrated at 43 in FIGS. 2 and 3. During such movement to position 43 the main ram also moves the container 30* to position 43. With the container 30, ram 40, and piercer at position 43 the piercer 41 may then be extended so that its outer end portion is extended through the container 30 and to a position immediately adjacent the front platen 32 of the press 20 and for reasons which will be apparent later in this specification.

The extrusion press 20 has blocking means shown as a skim block 45 which may be suitably fixed to the front end portion of the piercer 41 so that the skim block 45 may be moved through the cylindrical bore 34 both toward and away from the front platen 32 of the press 20. The skim block 45 has an outer cylindrical surface 46 which corresponds closely to the cylindrical surface 33 of the container 30 so as to provide a precisely controlled fit between the skim block 45 and the cylindrical bore 33. Further, the skim block 45 is preferably made of a high quality material so that it may be repeatedly used without damage or excessive wear thereto in removing unextruded billet residue, oxides, dirt, lubricants, etc. from the cylindrical inner surface of the container 30.

Having described in general terms certain components of an exemplary extrusion apparatus or press which may be utilized in carrying out the method of this invention, the description will now proceed with a detailed description of such method and it will be seen that this method provides all of the advantages of an indirect extrusion process while enabling an economical and efficient extrusion of metal billets in mass production quantities.

The indirect extrusion operation is commenced by loading a billet 35 within the cylindrical bore 33 of the container 30 and blocking the tool carrier 24 in its extruding position by lowering the gate lock 27 to its locking position at 29, see FIG. 1. With the billet 35 within the cylindrical bore 34 the skim block 45 is partially held in the bore '34 adjacent one end 51 of the container 30 to engage the corresponding end of the billet 35. The die means or die 26 is arranged adjacent the other or opposite end 52 of the container so that it engages the corresponding opposite end of the billet 35.

With the billet 35 thus positioned in the container 30 compressive forces are applied to opposite ends of the billet so that the skim block 45 (i.e., blocking means) and die means or die 26 are relatively moved toward each other causing the billet 35 to be extruded through orifice means shown as an orifice 54 provided in the die 26 and so that the resulting extruded elongated metallic member '55, see FIG. 2, extends through the longitudinal opening 56 in the hollow stem and through the opening 23 in the structural portion 21 of the press 20. The extruding action is continued until the billet 35 is substantially completely extruded so that a butt portion or unextruded butt 60 remains within the container as illustrated in FIG. 2.

Any suitable technique may be utilized to relatively move the skim block 45 and the extrusion die 26 toward each other to extrude the metal billet 35 while keeping the skim block more nearly adjacent the end 51 of the container 30. In this example of the invention the main ram 40 has an annular surface 61 which engages the container and has a recessed annular surface 62 which simultaneously engages the end of the skim block 45 which is remote from the front platen 32 so that with the skim block 45 held substantially in a fixed position relative to the annular surface 61 of the main ram 40 the container 30 and skim block 45 are moved together by the ram 40 toward the front platen 32 from the remote position 42 shown in FIG. 1 to the forward position 43 shown in FIG. 2 to extrude the billet through the orifice 54. At the completion of the extrusion operation the movement of the main ram is stopped so that the unextruded butt 60 is arranged more nearly adjacent the end of the container 30 remote from the front platen 32 and as illustrated in FIG. 2.

With the billet 35 substantially completely extruded the gate look 27 is lifted to its upper position 28 to thereby release the tool carrier 24 so that the hollow stem 25 and die 26 may be moved away from the front end of main ram 40 and through the container 30.

During the indirect extrusion operation there is an accumulation of skull, shown as a skull layer 65, on the cylindrical inner surface 33 of the container 30 and the layer 65 is shown having an exaggerated thickness. This skull contains undesirable materials, such as metal oxide, lubricant, and other impurities. Unless the skull is removed, these materials will find their way into the extrusions, thereby lessening their quality and possibly rendering them defective.

The skull layer 65 is removed in a simple manner by moving the closely fitting skim block 45 through the container 30 and in this example the skim block is moved through such container from the remote end 51 toward the end 52 of such container. Any suitable moving device may be provided to move the skim block 45 and, in this example of the invention, the skim block 45 is moved by extending the piercer 41 away from the forward end of the main ram 40 toward the front platen 32- of the press 20 so that the skull layer 65 is removed from within the container 30 and added to the butt 60, which for purposes of illustration is shown to be of exaggerated thickness.

It will be apparent from FIG. 3 of the drawings that by moving the skim block 45 through the container the unextruded butt 60, die 26, and stem 25 are also moved through the container 30 so that the butt may be sheared from the extruded member 55 and the die 26 separated from the butt 60. The method of this invention may be carried out using a plurality of dies 26 so that each die 26 may be properly cleaned and conditioned after each extrusion operation.

The skimming operation, i.e., the removing of skull from within the container, has been described as being carried out by moving the skim block 45 through the stationary container 30 at the completion of the extrusion operation. However, it will be appreciated that the container 30 and ram 40 may be moved away from the front platen 32 while holding the skim block 45 in a substantially stationary position to accomplish the skull removal. Further, it may be desired to simultaneously move both the skim block 45 and the container 30 so that the net effect of such movement is to traverse the skim block through the container from the remote end 51 to the forward end 52 thereof and thereby remove any skull that may have accumulated on the inner surface 33.

After the skull layer has been removed from the container 30 the main ram 40 and container 30 are arranged at their forward position 43 which is more close- 1y adjacent the front platen 32 and with the container 30 in such forward position the piercer 41 is moved away from the front platen 32 to thereby move the skim block 45 therewith to a position within the container 30. With skim block 45 within such container it will be seen that the die 26 and butt 60 are supported by the hollow stem 25.

The press 20 has a supporting member which is utilized to support the forward end portion 71 of the stem 25, see FIG. 4, and the press has a shear 72 which is movable toward and away from the supporting member 70. Once the skim block 45 is moved away from the die 26 the shear 72 and supporting member 70 are used in a cooperating manner to shear the butt 60 and die 26 away from the extruded elongated member 55 whereupon the member 70 and shear 72 are returned to their normally retracted positions and the container 30 and main ram 40 (carrying piercer 41 therewith) are returned to their remote position 42 shown in FIG. 1. If the die is secured to the stem, the shear will merely shear the butt from the die.

The press 20 has a billet charger or loader 73 which supports each new billet 35 which is to be extruded and also supports each die 26 in the manner illustrated in FIG. 5 of the drawings. The billet loader 73 has a support 74 fixed to the terminal end of a telescoping member 75 and the member 75 positions the support 74 so that the billet 35 may be loaded into the container 30 from end 52 thereof through which member 55 is normally extruded and which may be referred to as the extrusion end 52.

The loading of a billet 35 may be accomplished by any suitable technique; however, by loading from the extrusion end 52 of the container 30 the method of this invention may be carried out in efficient high-speed manner. In this example of the invention the billet 35 is pushed into the bore 34 by the stem 25 which has a terminal end which engages the die 26 to move the die and billet into the container essentially as shown in FIG.

6. The loading action is continued until the billet 35 and die 26 are in the position illustrated in FIG. 1 whereupon the billet loader 73 is moved from the soild line position of FIG. 6 to a dotted line position designated by the reference numeral at 82.

By using the stem 25 and tool carrier 24 to charge the billet 35 within the container 30 it will be seen that the carrier 24 is simultaneously positioned to enable the gate lock 27 to be lowered and commence another extrusion and skull removal operation in the manner previously described.

The disclosure of the unique method of this invention has been presented without a detailed description of the actuators, or other suitable moving means, which may be used to move components such as the main ram 40, the piercer 41, the container 30, tool carrier 24, the gate lock 27, the shear 72, and the support 70; however, it will be appreciated that any suitable moving means may be provided for moving these various components as required and in any known manner. For example, hydraulic actuators may be utilized to move all of these components.

In this exemplary presentation of the invention the skim block 45 is described as having a cylindrical outer surface 46 which corresponds to and is adapted to fit closely within the cylindrical surface 33 of the container 30. However, it is to be understood that reference to a cylindrical surface does not necessarily refer to a right circular cylindrical surface. Further, the surface 33 provided within the container 30 may have any desired configuration whereby the skim block will have a corresponding peripheral configuration so that the skim block will fit closely within the container and enable the skimming of skull from within the inside surface of the container at the completion of each indirect extrusion operation.

While present exemplary embodiments of this invention, and methods of practicing the same, have been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced within the scope of the following claims.

What is claimed is:

1. A process of operating an extrusion press having a front platen, a hollow stem supported by said front platen for movement with respect thereto, die means having an orifice and being' engageable with said hollow stem, a container movable over said hollow stem, a ram adapted to abut the rear of said container, and blocking means carried by and movable with respect to said ram into said container, said process comprising the steps of:

(a) disposing a metal billet in said container;

Cit

(b) holding said hollow stem fixed with respect to said front platen;

(c)- advancing said ram and said blocking means so that said billet is compressed between said blocking means and said die means and then extruded through said orifice in said die means until said die means is, near said blocking means toward the rear of said container;

(d) releasing said hollow stem for axial movement with respect to said front platen; and

(e) advancing said blocking means, the butt of said billet, said die means, and said hollow stem together, thereby removing unextruded billet residue through the front of said container.

2. The process of claim 1 wherein step (a) is efiected by the rearward movement of said hollow stem with respect to said front platen.

3. The process of claim 1 wherein steps (b) and (d) are efiected by the engagement and disengagement, respectively, of a gate lock.

4. The process of claim 1 wherein during step (e) said blocking means skims unextruded billet residue from the inner surface of said container.

5. The process of claim 1 wherein during step (e) said hollow stem telescopes within said! front platen.

6. The process of claim 1 wherein: step (a) is effected by the rearward movement of said hollow stem with respect to said front platen; steps (b) and (d) are effected by the engagement and disengagement, respectively, of a gate lock; and during step (e) said] blocking means skims unextruded billet residue from the inner surface of said container and said hollow stem telescopes within said front platen.

7. The process of claim 4 wherein the diameter of said blocking means is greater than the diameter of said die means.

References Cited UNITED STATES PATENTS 1,661,594 3/1928 Born 72273 2,920,760 1/ 1960 Genders 72-259 3,073,442 1/ 1963 Miiller 72255X 1,609,988 12/1926 Bull 72--255 3,184,944 5/1965 Sibler 7225 5 2,675,125 4/ 1954 Genders 72-271 1,603,435 10/ 1926 Webster 72-272 CHARLES W. LANHAM, Primary Examiner A. L. HAVIS, Assistant Examiner U.S. Cl. X.R. 72-273 

